ANTECEDENT RETENTION INDEXES PREDICT SOIL MOISTURE

TWO MODELS FOR CALCULATING ANTECEDENT MOISTURE INDEX VALUES ARE EVALUATED BY COMPARISONS WITH MEASURE SOIL MOISTURE. ONE MODEL, BASED ON THE TRADITIONAL ANTECEDENT PRECIPITATION INDEX EQUATION, DEPLETES THE VALUES EXPONENTIALLY. THE SECOND MODEL DEPLETES THE INDEX VALUES BY AN EVAPOTRANSPIRATION-SOIL MOISTURE RELATION. INDEX VALUES COMPUTED BY THE TRADITIONAL EXPONENTIAL MODEL WITH RECOMMENDED K VALUES OF 0.88 AND 0.92 COMPARE POORLY WITH MEASURED SOIL MOISTURE. DERIVED K VALUES SHOW A DISTINCT SEASONAL TREND AND RANGE FROM 0.98 IN THE SPRING AND FALL TO 0.92 IN THE SUMMER WHEN REPRESENTING THE 0- TO 12-IN. SOIL DEPTH, AND 0.98 TO 0.96 WHEN REPRESENTING THE 0- TO 36-IN. SOIL DEPTH. INDEX VALUES BY BOTH MODELS COMPARE FAVORABLY WITH AVAILABLE SOIL MOISTURE WHEN DERIVED K AND PET VALUES ARE USED. THE K AND PET VALUES ARE RELATED TO PAN EVAPORATION TO FACILITATE THEIR PREDICTION AT OTHER LOCATIONS. (AUTHOR)

• Supplemental Notes:
  • Vol 93, No HY4, PROC PAPER 5351, PP 223-241
• Authors:
  • Saxton, K E
  • Lenz, A T
• Publication Date: 1967-7

Media Info

• Serial:
  • Journal of the Hydraulics Division
  • Publisher: American Society of Civil Engineers

Subject/Index Terms

• TRT Terms: Evapotranspiration; Forecasting; Indexes (Information management); Mathematical models; Retaining walls; Seasons; Soil water
• Uncontrolled Terms: Models; Seasonal variations
• Old TRIS Terms: Precipitation; Retaining
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00237365
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 1 1994 12:00AM